import torch
import torch.nn as nn
import torch.nn.functional as F
import torch.nn.init as init
import numpy as np


class ResnetConditionHR(nn.Module):
	def __init__(self, input_nc, output_nc, ngf=64, nf_part=64,norm_layer=nn.BatchNorm2d, use_dropout=False, n_blocks1=7, n_blocks2=3, padding_type='reflect'):
		assert(n_blocks1 >= 0); assert(n_blocks2 >= 0)
		super(ResnetConditionHR, self).__init__()
		self.input_nc = input_nc
		self.output_nc = output_nc
		self.ngf = ngf
		use_bias=True

		#main encoder output 256xW/4xH/4
		model_enc1 = [nn.ReflectionPad2d(3),nn.Conv2d(input_nc[0], ngf, kernel_size=7, padding=0,bias=use_bias),norm_layer(ngf),nn.ReLU(True)]
		model_enc1 += [nn.Conv2d(ngf , ngf * 2, kernel_size=3,stride=2, padding=1, bias=use_bias),norm_layer(ngf * 2),nn.ReLU(True)]
		model_enc2 = [nn.Conv2d(ngf*2 , ngf * 4, kernel_size=3,stride=2, padding=1, bias=use_bias),norm_layer(ngf * 4),nn.ReLU(True)]
		

		#back encoder output 256xW/4xH/4
		model_enc_back = [nn.ReflectionPad2d(3),nn.Conv2d(input_nc[1], ngf, kernel_size=7, padding=0,bias=use_bias),norm_layer(ngf),nn.ReLU(True)]
		n_downsampling = 2
		for i in range(n_downsampling):
			mult = 2**i
			model_enc_back += [nn.Conv2d(ngf * mult, ngf * mult * 2, kernel_size=3,stride=2, padding=1, bias=use_bias),norm_layer(ngf * mult * 2),nn.ReLU(True)]

		#seg encoder output 256xW/4xH/4
		model_enc_seg = [nn.ReflectionPad2d(3),nn.Conv2d(input_nc[2], ngf, kernel_size=7, padding=0,bias=use_bias),norm_layer(ngf),nn.ReLU(True)]
		n_downsampling = 2
		for i in range(n_downsampling):
			mult = 2**i
			model_enc_seg += [nn.Conv2d(ngf * mult, ngf * mult * 2, kernel_size=3,stride=2, padding=1, bias=use_bias),norm_layer(ngf * mult * 2),nn.ReLU(True)]

		mult = 2**n_downsampling

		# #motion encoder output 256xW/4xH/4
		model_enc_multi = [nn.ReflectionPad2d(3),nn.Conv2d(input_nc[3], ngf, kernel_size=7, padding=0,bias=use_bias),norm_layer(ngf),nn.ReLU(True)]
		n_downsampling = 2
		for i in range(n_downsampling):
			mult = 2**i
			model_enc_multi += [nn.Conv2d(ngf * mult, ngf * mult * 2, kernel_size=3,stride=2, padding=1, bias=use_bias),norm_layer(ngf * mult * 2),nn.ReLU(True)]


		self.model_enc1 = nn.Sequential(*model_enc1)
		self.model_enc2 = nn.Sequential(*model_enc2)
		self.model_enc_back = nn.Sequential(*model_enc_back)
		self.model_enc_seg = nn.Sequential(*model_enc_seg)
		self.model_enc_multi = nn.Sequential(*model_enc_multi)

		mult = 2**n_downsampling
		self.comb_back=nn.Sequential(nn.Conv2d(ngf * mult*2,nf_part,kernel_size=1,stride=1,padding=0,bias=False),norm_layer(ngf),nn.ReLU(True))
		self.comb_seg=nn.Sequential(nn.Conv2d(ngf * mult*2,nf_part,kernel_size=1,stride=1,padding=0,bias=False),norm_layer(ngf),nn.ReLU(True))
		self.comb_multi=nn.Sequential(nn.Conv2d(ngf * mult*2,nf_part,kernel_size=1,stride=1,padding=0,bias=False),norm_layer(ngf),nn.ReLU(True))

		#decoder
		model_res_dec=[nn.Conv2d(ngf * mult +3*nf_part,ngf*mult,kernel_size=1,stride=1,padding=0,bias=False),norm_layer(ngf*mult),nn.ReLU(True)]
		for i in range(n_blocks1):
			model_res_dec += [ResnetBlock(ngf * mult, padding_type=padding_type, norm_layer=norm_layer, use_dropout=use_dropout, use_bias=use_bias)]

		model_res_dec_al=[]
		for i in range(n_blocks2):
			model_res_dec_al += [ResnetBlock(ngf * mult, padding_type=padding_type, norm_layer=norm_layer, use_dropout=use_dropout, use_bias=use_bias)]

		model_res_dec_fg=[]
		for i in range(n_blocks2):
			model_res_dec_fg += [ResnetBlock(ngf * mult, padding_type=padding_type, norm_layer=norm_layer, use_dropout=use_dropout, use_bias=use_bias)]

		model_dec_al=[]
		for i in range(n_downsampling):
			mult = 2**(n_downsampling - i)
			#model_dec_al += [nn.ConvTranspose2d(ngf * mult, int(ngf * mult / 2),kernel_size=3, stride=2,padding=1, output_padding=1,bias=use_bias),norm_layer(int(ngf * mult / 2)),nn.ReLU(True)]
			model_dec_al += [nn.Upsample(scale_factor=2,mode='bilinear',align_corners = True),nn.Conv2d(ngf * mult, int(ngf * mult / 2), 3, stride=1,padding=1),norm_layer(int(ngf * mult / 2)),nn.ReLU(True)]
		model_dec_al += [nn.ReflectionPad2d(3),nn.Conv2d(ngf, 1, kernel_size=7, padding=0),nn.Tanh()]


		model_dec_fg1=[nn.Upsample(scale_factor=2,mode='bilinear',align_corners = True),nn.Conv2d(ngf * 4, int(ngf * 2), 3, stride=1,padding=1),norm_layer(int(ngf * 2)),nn.ReLU(True)]
		model_dec_fg2=[nn.Upsample(scale_factor=2,mode='bilinear',align_corners = True),nn.Conv2d(ngf * 4, ngf, 3, stride=1,padding=1),norm_layer(ngf),nn.ReLU(True),nn.ReflectionPad2d(3),nn.Conv2d(ngf, output_nc-1, kernel_size=7, padding=0)]

		self.model_res_dec = nn.Sequential(*model_res_dec)
		self.model_res_dec_al=nn.Sequential(*model_res_dec_al)
		self.model_res_dec_fg=nn.Sequential(*model_res_dec_fg)
		self.model_al_out=nn.Sequential(*model_dec_al)

		self.model_dec_fg1=nn.Sequential(*model_dec_fg1)
		self.model_fg_out = nn.Sequential(*model_dec_fg2)
		

	def forward(self, image,back,seg,multi):
		img_feat1=self.model_enc1(image)
		img_feat=self.model_enc2(img_feat1)

		back_feat=self.model_enc_back(back)
		seg_feat=self.model_enc_seg(seg)
		multi_feat=self.model_enc_multi(multi)

		oth_feat=torch.cat([self.comb_back(torch.cat([img_feat,back_feat],dim=1)),self.comb_seg(torch.cat([img_feat,seg_feat],dim=1)),self.comb_multi(torch.cat([img_feat,back_feat],dim=1))],dim=1)

		out_dec=self.model_res_dec(torch.cat([img_feat,oth_feat],dim=1))

		out_dec_al=self.model_res_dec_al(out_dec)
		al_out=self.model_al_out(out_dec_al)

		out_dec_fg=self.model_res_dec_fg(out_dec)
		out_dec_fg1=self.model_dec_fg1(out_dec_fg)
		fg_out=self.model_fg_out(torch.cat([out_dec_fg1,img_feat1],dim=1))


		return al_out, fg_out

############################## part ##################################



def conv_init(m):
	classname = m.__class__.__name__
	if classname.find('Conv') != -1:
		init.xavier_uniform(m.weight, gain=np.sqrt(2))
		#init.normal(m.weight)
		if m.bias is not None:
			init.constant(m.bias, 0)

	if classname.find('Linear') != -1:
		init.normal(m.weight)
		init.constant(m.bias,1)

	if classname.find('BatchNorm2d') != -1:
		init.normal(m.weight.data, 1.0, 0.2)
		init.constant(m.bias.data, 0.0)

class conv3x3(nn.Module):
	'''(conv => BN => ReLU)'''
	def __init__(self, in_ch, out_ch):
		super(conv3x3, self).__init__()
		self.conv = nn.Sequential(
			nn.Conv2d(in_ch, out_ch, 3, stride=2,padding=1),
			nn.BatchNorm2d(out_ch),
			nn.LeakyReLU(0.2,inplace=True),
		)

	def forward(self, x):
		x = self.conv(x)
		return x

class conv3x3s1(nn.Module):
	'''(conv => BN => ReLU)'''
	def __init__(self, in_ch, out_ch):
		super(conv3x3s1, self).__init__()
		self.conv = nn.Sequential(
			nn.Conv2d(in_ch, out_ch, 3, stride=1,padding=1),
			nn.BatchNorm2d(out_ch),
			nn.LeakyReLU(0.2,inplace=True),
		)

	def forward(self, x):
		x = self.conv(x)
		return x




class conv1x1(nn.Module):
	'''(conv => BN => ReLU)'''
	def __init__(self, in_ch, out_ch):
		super(conv1x1, self).__init__()
		self.conv = nn.Sequential(
			nn.Conv2d(in_ch, out_ch, 1, stride=1,padding=0),
			nn.BatchNorm2d(out_ch),
			nn.LeakyReLU(0.2,inplace=True),
		)

	def forward(self, x):
		x = self.conv(x)
		return x



class upconv3x3(nn.Module):
	def __init__(self, in_ch, out_ch):
		super(upconv3x3, self).__init__()
		self.conv = nn.Sequential(
			nn.Upsample(scale_factor=2,mode='bilinear'),
			nn.Conv2d(in_ch, out_ch, 3, stride=1,padding=1),
			nn.BatchNorm2d(out_ch),
			nn.ReLU(inplace=True),
		)
	def forward(self, x):
		x=self.conv(x)
		return x

class fc(nn.Module):
	def __init__(self,in_ch,out_ch):
		super(fc,self).__init__()
		self.fullc = nn.Sequential(
			nn.Linear(in_ch,out_ch),
			nn.ReLU(inplace=True),
		)
	def forward(self,x):
		x=self.fullc(x)
		return x

# Define a resnet block
class ResnetBlock(nn.Module):
	def __init__(self, dim, padding_type, norm_layer, use_dropout, use_bias):
		super(ResnetBlock, self).__init__()
		self.conv_block = self.build_conv_block(dim, padding_type, norm_layer, use_dropout, use_bias)

	def build_conv_block(self, dim, padding_type, norm_layer, use_dropout, use_bias):
		conv_block = []
		p = 0
		if padding_type == 'reflect':
			conv_block += [nn.ReflectionPad2d(1)]
		elif padding_type == 'replicate':
			conv_block += [nn.ReplicationPad2d(1)]
		elif padding_type == 'zero':
			p = 1
		else:
			raise NotImplementedError('padding [%s] is not implemented' % padding_type)

		conv_block += [nn.Conv2d(dim, dim, kernel_size=3, padding=p, bias=use_bias),
					   norm_layer(dim),
					   nn.ReLU(True)]
		if use_dropout:
			conv_block += [nn.Dropout(0.5)]

		p = 0
		if padding_type == 'reflect':
			conv_block += [nn.ReflectionPad2d(1)]
		elif padding_type == 'replicate':
			conv_block += [nn.ReplicationPad2d(1)]
		elif padding_type == 'zero':
			p = 1
		else:
			raise NotImplementedError('padding [%s] is not implemented' % padding_type)
		conv_block += [nn.Conv2d(dim, dim, kernel_size=3, padding=p, bias=use_bias),
					   norm_layer(dim)]

		return nn.Sequential(*conv_block)

	def forward(self, x):
		out = x + self.conv_block(x)
		return out

